Durian is highly sensitive to chilling temperatures, which restrict its cultivation beyond tropical regions. In this study, one-year-old seedlings of the cultivars ‘Musang King’ and ‘Monthong’ were exposed to 10 °C for 7 days to characterize their phenotypic, physiological, and transcriptional responses. Leaf phenotype, membrane injury, osmotic adjustment, photosynthetic pigment contents, amylase activity, and antioxidant enzyme activities were evaluated, and transcriptome sequencing was performed using samples collected before chilling treatment and after 1 and 5 days of exposure. ‘Monthong’ exhibited earlier and visually more extensive leaf abscission than ‘Musang King’, while the two cultivars showed contrasting temporal patterns of malondialdehyde accumulation and antioxidant enzyme activities. Comparative transcriptome analysis was subsequently used to construct a Musang King-focused discovery set comprising genes prioritized based on progressive induction patterns and higher transcript abundance in ‘Musang King’. Because AP2/ERF transcription factors were represented in this discovery set, the DREB gene family was characterized at the whole-genome level. A total of 81 DzDREB genes were identified and classified into six subgroups. Integration of transcriptomic response patterns, stress-related functional annotations, and promoter cis-regulatory elements supported the prioritization of a ten-gene DzDREB panel for further investigation. Exploratory seasonal field-expression profiling provided additional support for seven candidates, among which DzDREB36, DzDREB45, DzDREB62, and DzDREB66 showed comparatively stronger support across datasets. These results provide candidate resources for further functional investigation of differential chilling responses in durian.

Durian (Durio zibethinus) germplasm may be incorrectly named, mislabeled, or genetically misidentified during introduction, exchange, and nursery stock distribution. Morphological identification is also affected by environmental conditions and plant developmental stages. A core simple sequence repeat (SSR) marker set was developed for the identification of durian germplasm. Genome-wide mining identified 106,776 SSR loci in the durian reference genome, and 18 stable and polymorphic markers were selected from 160 candidate primer pairs through agarose gel screening and M13-tailed fluorescent capillary electrophoresis. A total of 142 alleles were detected at the 18 SSR loci across the 58 durian accessions, with 3–15 alleles per locus and PIC values ranging from 0.422 to 0.849. Exhaustive evaluation of all marker combinations identified a minimum six-locus core SSR marker set comprising Y6, Y12, Y15, Y75, Y91, and Y108, which generated unique multilocus genotypes for all 58 accessions in the current validation panel, with a cumulative probability of identity (PID) of 7.99 × 10⁻⁸. STRUCTURE analysis, with K representing the number of inferred genetic clusters, supported K = 8 and revealed admixture in several accessions. The core SSR marker set developed in this study can distinguish the 58 durian accessions and be used to construct their DNA fingerprints. Validation in larger and more genetically diverse germplasm collections is required before routine commercial deployment.

Hainan is the dominant production area of the red-fleshed pitaya (Hylocereus undatus) cv. ‘Jindu No.1’ in China, and cutting propagation is the main method for its large-scale seedling cultivation. Plant growth regulators (PGRs) are the key factors regulating the rooting of cuttings. Existing studies mostly focus on the concentration optimization of a single agent, lack systematic broad-spectrum screening of commonly used PGRs in agriculture, and have the problem of disconnection between laboratory results and field production. To screen an efficient root-promoting PGR scheme suitable for large-scale seedling cultivation in Hainan production areas, this study established a three-level experimental system of “broad-spectrum primary screening→gradient re-screening→soil culture scenario verification”, used 14 kinds of PGRs commonly used in agricultural production as materials, and carried out a systematic evaluation combined with principal component analysis (PCA). 1-naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA) and potassium indole-3-butyrate (K-IBA) were identified as high-efficiency agents in the primary screening, with a rooting rate of 100%, and the core root morphological indexes were significantly better than those of the water control (p < 0.05). Two independent experiments verified the stability of the “total growth–thickness” binary regulation mechanism of the pitaya root system. In the re-screening test, 400 mg·L⁻¹ NAA had the best comprehensive performance, synergistically improving the total root growth and root thickness, and 125 mg·L⁻¹ K-IBA had the most significant effect in promoting the longitudinal extension of roots, with the average root length increased by 760.0% compared with the control. Soil culture tests confirmed that the two optimal schemes had stable and reliable application effects in field substrate cultivation. The results of this study can provide technical support for the large-scale seedling cultivation of ‘Jindu No.1’ pitaya, and the established three-level screening system also provides a methodological reference for PGR screening in cutting propagation of similar tropical crops.